The present invention relates to a security device and particularly, to a security device that prevents the information from inside of the device being stolen by disassembling a case of the device.
In recent years, there have been strong needs for a security function for information in electronic equipment such as a personal computer. Especially, there are many cases where a storage device such as a hard disk with information stored therein is stolen, and countermeasures against the information theft will be required in the future. Sometimes illegal adaptations are made by disassembling the electronic equipment, therefore, there is a need of a means for determining adaptation""s history or the like in order to provide security against the illegal adaptations.
At present, in order to provide a security, the information is stored in a coded form, while, as a countermeasure against disassembly of a device, special screws are provided so that the construction becomes difficult to be disassembled by an ordinary users. However, even when data is stored in a coded form, or even when special screws are provided, these measures do not protect the information medium itself. Furthermore, after a theft, there is ample of time for decoding of the data, hence there still uneasiness in the security of information.
Under those circumstances, as disclosed in Japanese Patent Laid-Open Publication No. HEI 6-12589, there has been proposed a technique for detecting not only disassembly of a case but also a hole made thereon or destruction by installing signal lines on an inner surface of a housing and detecting disconnection of any of the lines. In addition to it, as disclosed in Japanese Patent Laid-Open Publication No. SHO 63-76347, there has been proposed a technique for deleting internal data with a switching mechanism provided in the casing which is actuated when the casing is disassembled.
In the technique in Japanese Patent Laid-Open Publication No. HEI 6-12589, detection of destruction of a casing is possible, however, because signal line are placed throughout the internal surface of the casing, an increase in the detection points makes the construction for realizing the security function more complicated. Especially, in Japanese Patent Laid-Open Publication No. SHO 64-76347, as a special switching construction is provided inside the casing, the switching function works in response to disassembly of the casing, which also makes construction of the casing complicated. As described above, the constructions disclosed in the two Publications above are electrically and mechanically complicated only for the purpose of performing the security function.
It is an object of the present invention to provide, for solving the problems described above, a security device which can ensure security against leakage of information with simple configuration.
With the present invention, contact positions of a printed board and those of a casing are electrically connected, and a state in which the contact positions are separated is electrically detected, so that the moment at which the electronic equipment is disassembled can be detected, and with this feature, security for electronic equipment can be insured with simple configuration.
With the present invention, at least a portion of a casing comprises a frame ground with its contact position as a terminal, and a contact position on at least a portion of a printed board comprises a terminal, so that the electrically connected state between the positions can be maintained with simple configuration.
With the present invention, the contact positions are connected with a pull-up resistor, so that an act of disassembling a case can easily be detected with electric changes between HIGH and LOW.
With the present invention, when separation between contact positions is detected, an alarm is generated, so that illegal acts such as theft can be alerted to the surrounding people with simple configuration, and with this feature, security against theft of information can be insured.
With the present invention, when separation between contact positions is detected, data is rewritten, so that, even if data is illegally acquired, the contents of the data would have been broken out, which can prevent the data itself from theft, and with this feature, security against theft of information can be insured with simple configuration.
With the present invention, a state in which separation between contact positions has been detected is maintained, and power supply to electronic equipment is shut down while the state is maintained, so that, when it is found that the equipment has been disassembled once for the purpose of illegal adaptations on the equipment or its unauthorized use, the use of the equipment is forcefully inhibited thereafter, and with this feature, unauthorized use of the equipment due to reassembly after its being shipped can be prevented before its use, and for this reason, security against theft of information can be insured with simple configuration.
With the present invention, a state in which separation between contact positions has been detected is maintained, and an operation of the electronic equipment is reset while the state is maintained, so that, when it is found that the equipment has been disassembled once for the purpose of illegal adaptations on the equipment or its unauthorized use, the use of the equipment is forcefully inhibited thereafter regardless of power supply being effected or not, and with this feature, unauthorized use of the equipment due to reassembly after its being shipped can be prevented before its use, and for this reason, security against theft of information can be insured with simple configuration.
With the present invention, counting is executed each time a separation between contact positions is detected, and the count is read out under the authorization, so that, when it is found that the equipment has been disassembled once for the purpose of illegal adaptations on the equipment or its unauthorized use, the history thereof is maintained, and with this feature, determination can be made as to whether there has been any change in the equipment for an illegal purpose or the like or not, and for this reason, security against theft of information can be insured with simple configuration.
Other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.